I'm trying to make a timeline of momentum for my physics class and I keep running across a paper by Jean Buridan called QM XII.9: 73ra. I don't know what any of this means, and I don't know how to find the work on my own. If someone could help me find it or tell me how to decipher the title that would be great. Thanks.

2 Answers 2


On John Buridan's page in the Stanford Encyclopedia of Philosophy, we have the citation:

Buridan, John, 1588 (actually 1518), In Metaphysicen Aristotelis Questiones argutissimae, Paris. Rpr. 1964, as Kommentar zur Aristotelischen Metaphysik, Frankfurt a. M.: Minerva. [QM]

which suggests that the 'QM' in your citation is 'In Metaphysicen Aristotelis Questiones argutissimae'.

This identification is confirmed in the paper John Buridan's Solution to the Problem of Universals, by Peter King of Toronto University, p27.

A copy of the text of 'In Metaphysicen Aristotelis Questiones argutissimae' (in Latin!) is available to view on Google Books or the BnF Gallica site. In this case, the page you are interested in (see below) is probably easier to read on the Google Books version.

The original text is in Latin, but a translation of the passage you are interested in is actually provided on the Stanford Encyclopedia of Philosophy page cited above:

”after leaving the arm of the thrower, the projectile would be moved by an impetus given to it by the thrower, and would continue to be moved as long as the impetus remained stronger than the resistance, and would be of infinite duration were it not diminished and corrupted by a contrary force resisting it or by something inclining it to a contrary motion”

More generally, to understand a citation of this sort, you also need to understand a little of the language of palaeography and manuscript studies.

The XII.9 is relatively straightforward. It simply means:

  • Liber XII (Book 12)
  • Quaestio 9 (Question 9) [in the general case, the second number will often refer to the chapter or 'capitulum', frequently abbreviated to 'cap']

However, the '73ra' is the bit that requires some understanding of the specialist terminology.

A single sheet of writing material is called a 'folio'. In a case like this where the folios have been bound together, this will be a single page of the manuscript book.

The front side of a folio is called the 'recto', the back is the 'verso'.

When manuscripts are written in columns, the columns are conventionally referred to alphabetically from left to right. In this case, we have two columns, so the left-hand column is referred to as 'column a' and the right-hand column as 'column b'.

So, in your example, '73ra' means:

  • folio 73 (LXXIII),
  • recto,
  • column a.

(This is towards the end of the book in this case!)

  • According to Peter King (Toronto University), "QM" could be Quaestiones in Metaphysicen Aristotelis argutissimae. Footnote 2 in his paper, Jean Buridan's Philosophy of Science, in Studies in History and Philosophy of Science 18 (1987), 109-132, has the details of incorrect date as well.
    – J Asia
    Commented Apr 14, 2019 at 23:28
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    @JAsia I noticed that on another site. But the cited folio in In Metaphysicen Aristotelis Questiones argutissimae does discuss the question of momentum, so I suspect that this is the correct text in this case. This kind of thing happens far more often than it should, tbh. It's one reason that I find these non-standard "standard abbreviations" infuriating! Commented Apr 14, 2019 at 23:34
  • 1
    Lol, I feel you. In my previous life in law, my view of incorrect citations was it should be a capital offence! I added the note/comment to give OP more assurance on the mistaken date which you mentioned.
    – J Asia
    Commented Apr 14, 2019 at 23:37
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    @Mr.Guest Manuscripts in the 14th century would have been handwritten. Gutenberg's printing press was developed in the 15th century. From the biography on the Stanford Encyclopedia page it looks like the 1518 date is the first printed edition. The XII is 'Liber 12' ('Book 12'), as you can see in the linked printed version of the text. Commented Apr 15, 2019 at 3:16
  • 1
    @Mr.Guest When a community of scholars work on a particular subject, it becomes common to use abbreviations to refer to particular titles. It makes citations within the text shorter, and less distracting. It is good practice to list the texts and the abbreviations at the end of the article (as in the Peter King article I linked to in the answer). Sadly, not everyone follows the "standard abbreviation" conventions, and not everyone includes a list of the abbreviations used in their article. In those cases, search for related papers using Google until you find one that does. Commented Apr 15, 2019 at 3:21

The text you're looking for is Question XII.9 of Buridan's Questions on the "Metaphysics" of Aristotle. The question is, "are there as many celestial motions as there are intelligences (and vice versa)?"

The edition cited is the Minerva reprint of an early modern print edition, called Kommentar zur Aristotelischen Metaphysik.

Hope this helps!

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